The expansion of telecommunications incurs increasingly severe crosstalk and interference, and a physical layer cognitive method, called blind source separation (BSS), can effectively address these issues. BSS requires minimal prior knowledge to recover signals from their mixtures, agnostic to the carrier frequency, signal format, and channel conditions. However, previous electronic implementations did not fulfil this versatility due to the inherently narrow bandwidth of radio-frequency (RF) components, the high energy consumption of digital signal processors (DSP), and their shared weaknesses of low scalability.

In this presentation, I will talk about my work on developing photonic BSS approaches, which inherit the advantages of optical devices and fully fulfil the “blindness” aspect. Using a microring weight bank integrated on a photonic chip, we demonstrate energy-efficient, wavelength-division multiplexing (WDM) scalable BSS across 19.2 GHz processing bandwidth. Our system also has a high (9-bit) resolution for signal demixing thanks to a recently developed dithering control method, resulting in higher signal-to-interference ratios (SIR) even for ill-conditioned mixtures.

Further, I'll introduce our integration of a field-programmable gate array (FPGA) with the photonic BSS, enhancing real-time adaptability to dynamical interference. This has led to accelerated signal separation and the ability to continuously update demixing weights at rates up to 305 Hz. Moreover, this setup features a fully integrated photonic signal pathway in the analogue domain, enabling rapid demixing and recovery of the signal-of-interest in less than 15 picoseconds.

In parallel, I will explore the challenges and advancements in packaging and controlling silicon photonics. This field faces practical issues in these areas, where compact and robust setups are crucial for transforming innovative ideas into tangible demonstrations. I will share my experiences in transitioning from a traditional, bench-sized setup reliant on unreliable probes and bulky instruments to a streamlined, palm-sized system with fully integrated control and I/O.

Adviser: Paul Prucnal

Zoom Link: https://princeton.zoom.us/j/5477488401